Today we began Unit 4: Sun, Earth, Moon. For the next few months we will be studying everything from black holes to interstellar travel to moon phases and lunar eclipses. But before we begin, we must first study the science of gravity.
Gravity can most easily be defined as the force that pulls objects together. However, in reality, it’s more complicated than that. The strength of gravity depends on the mass of the planet, star, moon, or other object. Earth’s gravity, for example, is fairly strong; it produces an acceleration of 9.8 m/s per second in all objects. Yes, you read that right. All objects, even a bowling ball falling beside a feather, experience the same pull of gravity!
When air is taken out of the equation, we can see that gravity affects everything equally. But it’s strength can vary greatly from planet to planet. Mars, for example, has only about 38% of Earth’s gravitational pull, while the more massive Jupiter has 2.5 times the gravity of Earth. For the second half of class, students learned how to calculate what their weight would be (in lbs.) on six different objects in our solar system.